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HELP! I did a bad thing...

viffer_pilot

Guest
Guest
I posted this on the KLR forum but I'm adding here because I hope someone can provide me a solution I can use... File this under the category of no good deed goes unpunished. So I've been doing a bunch of stuff to the KLR. One of the "fixes" I planned to do was the banjo bolt upgrade to help with burning oil (which my 2008 does). Long story short, I cracked the housing where the middle banjo goes into the engine. The crack is worse on the outside than it is on the inside. I'm not sure how to proceed. The hole is stripped and the housing itself is cracked. If it was just the threads, I'd think a helicoil would work but with the crack... Anyone have a recommendation? Preferably one that does not require me to remove the engine. Seeing how much damage I've already caused, removing the engine is probably not something I should do...  Please don't judge...I feel stupid enough already.
 

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That was my original thought but I'm concerned about the metal shavings from drilling going into the engine where I can't get to them.  I don't know how I would do it without removing the engine and splitting the crankcase anyway.
 
I'm not familiar with the Klr but could you take the oil pan off before doing the repair and somehow flush the shavings through afterwards ?
 
Update.  A couple of the folks from the KLR Forum came back with very useful advice.  It appears that the hole doesn't actually go through the crank case.  It goes to an oil feeder tube that can be accessed with the clutch cover removed.  The best recommendation I have so far is to use a loctite product called Form-a-Thread.  It is a two part epoxy type product with a release agend that forms new threads in the hole.  The manufacturer says it can hold up to 128 ft-lbf.  I only need it to hold 20 (and not be cross threaded by some idiot with a wrench).  Fingers crossed.  Other option is to TIG weld and then use a Time-Sert flush mount insert but that is something beyond my capability.
 
I have used the exhaust from my shop vac hook to the oil fill hole
to blow any metal from the thread cutting out the hole where the
threads are being cut.
 
The epoxy repair is going to be a no-go.  I finally found a photo that I can read with the specs online and the max torque for an M10 bolt is 6.8 ft-lbf.  The spec for the banjo is 15 ft-lbf... I'm waiting to hear back from a local machinist to see if he's willing to do the work.  Even if the repair fails, I'm no worse than I am now.  I can't run the bike as it is and the only other option left to me is to replace the crankcase halves with a set from a donor bike.  $119 for the cases and about $250 for the  specialty tools and replacement seals (and 20-40 hours of my life).  I already have the tools to remove the flywheel so that's a blessing...I was wondering when I'd ever have to use them again.  :mad:
 
WOW... that stinks. No judging because I've done things similar to this. Some more "recoverable", others not  :-[
Thinking outside the box here...
When the threads stripped, they pushed out on the boss and cracked, so maybe if we can do something to add significant strength in the hoop direction, it might help. If the boss can be strengthened, then maybe you can use a Heli-Coil to restore the threads.
Measure the outside diameter of the boss, compensate for the fact that it was slightly expanded when it split (you want the original size of the boss, not the expanded size).
Make a thick-walled steel ring, with the ID just smaller than the diameter determined above. Give the ring a nice lead-in on one side. Not a thick washer, but a ring so it engages as much length of the boss as possible. Maybe grind away a little of that web to let the ring engage more of the boss.
Drive that ring over the boss. It needs to be tight to bring the boss back to its original shape. This is a little chancy because the boss has draft (larger diameter at the base than at the top).
Now you have the strength of the ring on the boss; do the Heli-Coil thing.
 
Jorge said:
Thinking outside the box here...
When the threads stripped, they pushed out on the boss and cracked, so maybe if we can do something to add significant strength in the hoop direction, it might help. If the boss can be strengthened, then maybe you can use a Heli-Coil to restore the threads.
Measure the outside diameter of the boss, compensate for the fact that it was slightly expanded when it split (you want the original size of the boss, not the expanded size).
Make a thick-walled steel ring, with the ID just smaller than the diameter determined above. Give the ring a nice lead-in on one side. Not a thick washer, but a ring so it engages as much length of the boss as possible. Maybe grind away a little of that web to let the ring engage more of the boss.
Drive that ring over the boss. It needs to be tight to bring the boss back to its original shape. This is a little chancy because the boss has draft (larger diameter at the base than at the top).
Now you have the strength of the ring on the boss; do the Heli-Coil thing.

I had this same exact thought.  Unfortunately, I couldn't get a micrometer into the area to get a good measurement.  I also don't have any way to machine the collar.  I think, this, combined with epoxy in the crack and a thread insert, would have been the ideal solution.

I did contact a machinist but he wouldn't touch a weld repair on an assembled engine.  Can't say I blame him.  It's very close to the crankcase seam.  If I'm going to tear the entire engine down, it makes more sense to replace the case halves vice repair.

I figured if I was going to have to replace the case anyway if the repair didn't work, I may as well try the epoxy repair.  I cleaned the area with degreaser and applied epoxy to the crack (original JB weld).  I was able to get some capillary action to to draw some of the epoxy into the crack.  I also applied some lockwire (0.041" T-304 SS) around the top and then put some JB weld over the crack and the lockwire and let that set up overnight.  Forgot to mention, I also chased the threads with a tap to clean them up as much as possible.

This morning I went and used the thread repair stuff to build up what was left of the threads.  That stuff sets up FAST!  I didn't get good threads on the first attempt so I had to do it again.  The threads now look pretty good and they are TIGHT but the bolt runs in and out.  Running torque is a little high but I get a pretty good feel that the threads are aligned.  I ordered some dowty washers to replace the crush washers on that banjo boss to get a more resilient seal.  I'll add some black RTV to the crack in the mating surface to help the washer seal.  The O-rings won't have as critical of a torque and the high running torque should help keep the bolt from backing out due to vibration.  As long as I can get a seal, I should be OK.  I'll have to do some short trips around the house to build up confidence in the repair before I start taking the bike to work (about 28 miles each way...all highway).  I'll update the post once I see if this worked.  If not, I'll get to learn how to disassemble an engine.  Yea...learning new things!
 
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